T-Amp > Audeze LCD-2 Surprise
Apr 10, 2011 at 9:03 PM Post #16 of 30

ETAHL

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Quote:
I used a 10ohm 10W resistor parallel to the headphones. 


I must be a mind reader.
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Apr 11, 2011 at 1:41 AM Post #17 of 30

brendon

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Just out of curiosity, how will this T-Amp perform considering it has a headphone out ?
 
Sorry I dont know much about amps but does the headphone out use the same speaker amp circuitry ?
 
http://cgi.ebay.com/Gold-TA2021-25WX2-Headphone-Amplifier-Tripath-Class-T-/250797541943?pt=LH_DefaultDomain_0&hash=item3a64b2ca37
 
Apr 11, 2011 at 2:45 AM Post #18 of 30

ETAHL

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In this amp, it has a separate headphone out circuit.
"C. Independence OP Amp 4558 for the headphone liner amplifier section."
 
Due to the non-common ground nature of T-amps, the only way to use the T-amp circuit is to use its speaker output connectors. The headphone cable needs to be modified or changed so each that each wire is connected to it own connector to the amp. In my case, I terminated the wires of my headphones with banana plugs that just plugs into the speaker connectors.
 
Quote:
Just out of curiosity, how will this T-Amp perform considering it has a headphone out ?
 
Sorry I dont know much about amps but does the headphone out use the same speaker amp circuitry ?
 
http://cgi.ebay.com/Gold-TA2021-25WX2-Headphone-Amplifier-Tripath-Class-T-/250797541943?pt=LH_DefaultDomain_0&hash=item3a64b2ca37



 
 
Apr 11, 2011 at 3:15 AM Post #19 of 30

brendon

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^^ Thanks for the feedback. Another related question. Would an adapter like this
 

 
along with a suitable 3.5mm -> RCA jack help connect a headphone to the speaker terminals on the T amp or am I grossly oversimplifying everything ?
redface.gif

 
Of course its not the best solution given the no of connections required but IF it would work it will be a viable cheap solution and your headphone cables will remain intact.
 
Apr 11, 2011 at 4:25 AM Post #20 of 30

ETAHL

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Unfortunately you can't convert a 3 contact 3.5mm or 1/4" plug to four. The grounds are still shorted together. You have to physically isolate the grounds, so each of the four wires are completely isolated. There is no getting around modifying the cable.
A simple solution is to cut off the 3.5mm plug and connect the wires to a 4 pin mini XLR male connector. Then make an adapter with 4 pin mini XLR female to four banana plugs; and also an adapter with 4 pin mini XLR female to stereo 3.5mm plug, so you can use your regular headphone amps. If you plan to go to a balanced amp in the future, you can also make another adapter to connect to the balanced amp. Lots of flexibility.
You can find all the connectors fairly cheap on ebay.
 
Quote:
^^ Thanks for the feedback. Another related question. Would an adapter like this
 

 
along with a suitable 3.5mm -> RCA jack help connect a headphone to the speaker terminals on the T amp or am I grossly oversimplifying everything ?
redface.gif

 
Of course its not the best solution given the no of connections required but IF it would work it will be a viable cheap solution and your headphone cables will remain intact.



 
 
Apr 12, 2011 at 4:46 PM Post #21 of 30

ETAHL

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I dug up a TA2020 T-amp circuit board I got from eBay for an unfinished project. I mod it for better used with headphones.
The gain was lowered by half, added additional filter capacitors, and purchased an inexpensive 12VDC car battery booster pack to power the T-amp.
Now the hiss can barely be heard. The extra filter capacitors and running on batteries further improves the sound quality.
The gain is still too high for my LCD-2, maximum listen level is still below 12 o'clock of the volume knob. I'll see if I can further cut down the gain and reduce the hiss to none audible levels.
These T-amps are such gems for headphone use. Guys with hard to drive orthodynamics should give these inexpensive T-amps a try.
I am surprise that headphone amp manufactures don't build T-amp power headphone amps; with XLR headphone connectors, they can get around the common ground obstacle of T-amps.
 
Apr 14, 2011 at 1:33 AM Post #23 of 30

ETAHL

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Quote:
Wonder how it stands up to the concerto with the LCD-2's



I do not have a Concerto to compare side by side. If you have a Matrix M-Stage, that is what I have as reference at the moment. The T-amp is definitely a good step up from the M-Stage with the LCD-2. I have been listening to the T-amp for the past few days. It is much more detail in general, more balance highs and solid bass. It is also has better sound stage. All the characteristics that make T-amps such giant killers of speaker amps are all there with the LCD-2.
 
I have since fine tune the T-amp to be more headphone friendly. I added an extra stage of filtering to cut down any T-amp modulating frequencies getting to the headphone; added 10 ohm pre-loading, significantly reduce the gain; added additional supply and noise filtering; and using a battery power supply. 
So far it sounds amazing with the LCD-2. I have to try really hard to hear any hiss. It now makes the M-Stage sound low rent, which it isn't.
o2smile.gif

 
Apr 25, 2011 at 7:08 PM Post #25 of 30

ETAHL

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Quote:
Interesting, only thing holding me back is needing a new cable for my cans. I assume a balanced cable should do.

WHich T-Amp do you use?


If you have a balanced cable you are almost there; all you need is an adapter to banana plugs and a couple of 8 ohm, 10 watt resistors.
I posted some images of the adapter on another thread:  http://www.head-fi.org/forum/thread/550890/what-is-a-t-amp

The T-amps I have used is the S.M.S.L SA36, either TA2020 or TA2024 version will work.
http://cgi.ebay.ca/New-TA2020-Class-T-Amp-Amplifier-Tripath-Chip-SA-36A-S-/170606603437?pt=Car_Amplifiers&hash=item27b8f22cad
 
I also have a very inexpensive TA2020 board as my experimental platform that I can easily mod. Later I plan to put it into a nice case with the proper connectors to be used with balanced headphone cables.
http://cgi.ebay.ca/Tripath-TA2020-PCB-25Watt-Class-T-Audio-Amplifier-Board-/230608706091?pt=AU_Electronics_Audio_Amplifiers&hash=item35b1599a2b
 
Both T-amps works well and very inexpensive.
 
Apr 25, 2011 at 10:53 PM Post #27 of 30

ETAHL

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Quote:
whats the diff between the 2024 and 2020 version>?
 
The 2024 version seems more expensive.


The TA2020 is higher power, mfg rated at 20W; where as the TA2024 is lower power, mfg rated at 15W.
Those are optimistic power ratings with 4 ohm loads at high distortion. Realistically the TA2020 is about 6W, and the TA2024, 5W at 8 ohm loads with low distortion.
The amp chips are also packaged differently, with the TA2024 smaller and surface mounted.
To me, they sound almost identical with the T2024 sounding a tiny bit better. The TA2024 version should be the less expensive of the two. I guess S.M.S.L is phasing out the TA2024; the TA2020 is much more common and competitively priced. My version is actually the older TA2024 version.
 
Mar 2, 2012 at 6:50 PM Post #28 of 30

Ilya--s

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Tried hlly tamp-20 with Hifiman HE4 and it's work pretty well with this hard-to-drive headphones. there is a little background noise, maybe it caused by poor power supply - but still, this noise is almost inaudible.
 
Mar 2, 2012 at 8:45 PM Post #29 of 30

ProtegeManiac

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Quote:
T-amps always seem underrated.



If you mean the dynamics, that's because they react quickly enough it's almost like having a Class A amp. When you factor everything else, like size and heat, the size of an 8wpc fullrange t-amp is still much smaller than a Class A of comparable power output. I'm actually wondering why no one's come up with a CMOY-size T-amp for headphones when there's a 2wpc version running off a 25v (I think) PSU, a variant of which is usually used for some panel TV speakers.
 
Aug 29, 2014 at 8:05 AM Post #30 of 30

Lefoobar

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I really really REALLY want to hear the T-amp with my LCD-2's. However, with no DIY/Recabling experience I'm a little reluctant to do anything (regardless of how easy it is). I was wondering, however, if anybody could provide a simple step by step guide on how to modify the amp/re-cable for me, or those who wish to begin experimenting with this sorta stuff? It doesn't sound too hard given what I've read. I could pick the parts up reasonably cheap and have a spare cable Audeze cable.
 

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